WO 99/06779 describes a shaft furnace for continuously heat-treating moulded bodies that contain carbon and are realized in the form of anodes in a column arrangement, in which the anodes are conveyed through a heating zone, a firing zone and a cooling zone of a furnace between tempering shafts by means of a conveying device. In the known method, the moulded bodies are arranged in moulded body rows that are positioned on top of one another and conveyed through heating shafts in a conveyor shaft on their path between an insertion station and a removal station. In this case, all of the moulded body rows arranged on top of one another form a moulded body column.
Due to the realization in the form of only one moulded body column, one respective tempering shaft is provided to both sides of the single moulded body column. The realization in the form of only one moulded body column also limits the production capacity to the height of the moulded body column. Based on the known method and the known device used for carrying out this method, the production capacity therefore can only be increased by correspondingly multiplying the entire furnace such that the installation of a complete system with increased production capacity also has a corresponding space requirement.
In this case, the space requirement for accommodating a plurality of the known furnaces is additionally increased due to the fact that burner devices provided in the firing zone of the known furnace are respectively arranged transverse to the two tempering shafts that extend in the longitudinal direction of the moulded body rows and therefore protrude laterally. Consequently, the width of the entire furnace is essentially defined by the laterally arranged burner devices, as well as the supply and the connecting lines connected to the burner devices.
Analogous to the continuous transport of the moulded body rows between the tempering shafts, the lateral arrangement of the burner devices promotes a non-uniform temperature distribution in the moulded bodies due to the formation of so-called “hot spots” such that moulded bodies with an irregular structure are produced and one has to accept the corresponding disadvantageous effects that, if the moulded bodies are realized in the form of anodes, manifest themselves in the form of an uneven electrode consumption.